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Biomedical subjects

P Guyon

Publications and source records attributed to P Guyon.

At least 19 recordsLinked to original sources

Thrombocytopenia and Plasmodium falciparum malaria in children with different exposures.

We studied thrombocytopenia during acute Plasmodium falciparum malaria in 64 traveller children from Paris (France), 85 children from Dakar (Senegal) with an intermittent exposure (69 with severe attack or cerebral malaria), and 81 children from Libreville (Gabon) with a perennial exposure (43 with severe attack or cerebral malaria). Initial thrombocytopenia was present in 43-58% of children with P falciparum malaria but was not more frequent in severe outcome or cerebral malaria. Low parasitaemia may lead to the misdiagnosis of malaria and delayed treatment when there is associated thrombocytopenia

Acute Disease↗

[Pertinence of the 2000 WHO criteria in non-immune children with severe malaria in Dakar, Senegal ].

UNLABELLED: The relevance of World Health Organization (WHO) criteria for severe malaria has not been assessed in non-immune children. The objectives of this study were (i) to evaluate the significance of 1990 WHO definition reconsidered in 2000 on distribution and lethality of severe cases in children admitted with falciparum malaria, and (ii) to contribute to the study of relevance of the WHO severe criteria in Dakar, an hypoendemic area in Senegal. PATIENTS AND METHODS: The 1990 WHO criteria, respiratory distress and platelet counts were prospectively collected in 1997-99 from children admitted to Hôpital Principal de Dakar, Senegal, with falciparum malaria diagnosed on a thick blood film. This method allowed also the definition of severe cases according to 2000 WHO criteria. RESULTS: Among 311 patients (median age: 8 years old), according to the 2000 WHO criteria, the frequency of severe malaria cases was increased by 23% (75% versus 52%) and case-fatality rates thereof were decreased by 5% (17% versus 12%) compared with 1990 WHO definition. One death occurred among cases defined as severe on admission only according to criteria modified by WHO in 2000. A multivariate logistic regression model identified several independent prognostic factors: cerebral malaria, hypoglycaemia, respiratory distress, renal failure, collapse, abnormal bleedings, pupillary abnormalities and thrombocytopaenia defined as a platelet count below 100,000/mm3. A significant association (p < 0.001) was observed between platelet count increase and consciousness level improvement, evaluated on day of first platelet count control (time from admission: 1-7 d). Among survivors, a lesser improvement in coma score was associated with a decrease in platelet counts (p < 0.04). CONCLUSIONS: The 1990 WHO criteria, which predicted death among malaria cases in children living under stable falciparum transmission, are relevant in this series of non-immune children living in a low and seasonal transmission. Nevertheless new WHO criteria showed poor prognostic significance. However, the 2000 WHO definition was highly sensitive to detect severe malaria cases. These findings should be considered for managing severe malaria in migrant children.

Adolescent↗

[Epidemiology and prognosis of childhood cancers in Dakar, Senegal].

Childhood cancer has often been considered as a problem mainly affecting industrialized countries. In reality more than half of cases occur in developing countries where management and diagnosis are major issues. This retrospective study includes 130 children (0.3% of admissions) between the ages of 0 and 15 years hospitalized for malignant disease at the Principal Hospital in Dakar, Senegal between January 1, 1990 and December 31, 2000. Mean age was 97 months and M/F sex ratio was 1.2. Mean delay for admission was 3 months. The five most frequent cancers, accounting for 75% of cases, were leukemia (n = 28), lymphoma (n = 21), nephroblastoma (n = 21), retinoblastoma (n = 16) and osteochondrosarcoma (n = 10). Treatment was completed in 18% of cases. Half of patient were lost from follow-up. The cure rate was 10% overall and 50% for patients receiving complete treatment. The highest cure rate was achieved for nephroblastoma, i.e., 58% of cases treated. Management of childhood cancer in Africa is confronted with numerous problems, namely, paucity of specialized staff, absence of expert centers, shortage of anticancer drugs, lack of financial resources, and delay in treatment. These factors associated with frequent malnutrition and recurrent infectious diseases, greatly lower cure rates in comparison with industrialized countries.

Adolescent↗

[Epidemiology and prognosis of childhood injuries in Dakar, Senegal].

The impact of accidental injury on childhood morbidity and mortality in Africa is underestimated. The frequency and severity of accidents is high. This retrospective study includes 381 children (3% of admission) between the ages of 0 and 15 years hospitalized for accidental injury at the Principal Hospital in Dakar, Senegal, between January 1, 1997 and December 31, 2000. The annual incidence of childhood injury doubled over the 4-year study period. Mean age was 48 months and the M/F sex ratio was 1.7. The causes were trauma (n = 184) due to domestic accidents (n = 109 including 91 falls) or road accidents (n = 75), poisoning (n = 129 including 38 caustic soda burns), foreign body aspiration or ingestion (n = 30), burns (n = 18), and miscellaneous accidents (n = 20). Most fatalities (9%) were due to road accidents and falls. Rapid uncontrolled urbanization and problems of displaced rural populations in adapting to city living may account for the high frequency of falls from high buildings and road accidents. As in industrialized countries road accidents, though not the most frequent, are the most lethal. Lack of emergency services accounts for severity. Vigorous information campaigns and prevention action will be needed to lower the high morbidity and mortality of childhood injury in developing countries.

Accidental Falls↗

Stent placement compared with balloon angioplasty for small coronary arteries: in-hospital and 6-month clinical and angiographic results.

BACKGROUND: Stenting has been demonstrated to be superior to balloon angioplasty in de novo focal lesions located in large native vessels. However, in small vessels, the benefit of stenting remains questionable. METHODS AND RESULTS: A total of 381 symptomatic patients with de novo focal lesion located on a small coronary segment vessel (<3 mm) were randomly assigned to either stent implantation (192 patients; 197 lesions) or standard balloon angioplasty (189 patients; 198 lesions). The primary end point was the angiographic restenosis rate at 6 months, as determined by quantitative coronary angiography. On intention-to-treat analysis, angiographic success rate and major adverse cardiac events were comparable: 97.9% and 4.6% versus 93.9% and 5.8% in the stent group and the balloon group, respectively. After the procedure, a larger acute gain was achieved with stent placement (1.35+/-0.45 versus 0.94+/-0.47 mm, P=0.0001), resulting in a larger minimal lumen diameter (2.06+/-0.42 versus 1.70+/-0.46 mm, P=0.0001). At follow-up (obtained in 91% of patients), angiographic restenosis rate was 21% in the stent group versus 47% in the balloon group (P=0.0001), a risk reduction of 55%. Repeat target lesion revascularization was less frequent in the stent group (13% versus 25%, P=0.0006). CONCLUSIONS: Elective stent placement in small coronary arteries with focal de novo lesions is safe and associated with a marked reduction in restenosis rate and subsequent target lesion revascularization rate at 6 months.

Angioplasty, Balloon, Coronary↗

Characterization of novel di- and tricarboxylic acids in fine tropical aerosols.

Three unknown di- and tricarboxylic acids were characterized in the fine size fraction of aerosols which were collected during the wet season in the Amazon basin (Rondonia, Brazil). For the structural characterization of the methyl esters of these unknown compounds, mass spectrometry with electron ionization (EI) and tandem mass spectral techniques combined with gas chromatographic (GC) separation were employed. Fragment and parent ion spectra were recorded during elution of the GC peaks by linked scanning of the B and E sectors in combination with high-energy collision-induced dissociation. The fragmentation patterns of significant ions in the first-order EI spectra were also obtained for nonanedioic acid, which was examined as a model compound. The compounds were tentatively identified as 4-acetyloxyheptanedioic acid and cis and trans isomers of 5-hexene-1,1,6-tricarboxylic acid. Since there were indications of biomass burning during the aerosol sampling the di- and tricarboxylic acids characterized in the present work could be markers for biomass burning. Furthermore, the characterization of di- and tricarboxylic acids in the fine size fraction of atmospheric aerosols may be important for assessing the effects of organic aerosols in cloud formation.

Aerosols↗

Assessment of left ventricular regional wall motion by color kinesis technique: comparison with angiographic findings.

The analysis of segmental wall motion using two-dimensional (2-D) echocardiography is subjective with high interobserver variability. Color kinesis is a new technique providing a color-encoded map of endocardial motion. We evaluated the accuracy of color kinesis and 2-D for assessment of regional asynergy compared with left ventricular angiography as a reference method. Fifteen patients admitted for myocardial infarction were studied by echocardiography the day before left ventricular angiography. The left ventricle was divided into seven segments. Each segment was classified by two independent observers as normal or abnormal in 2-D and color kinesis. Accuracy of color kinesis and 2-D was evaluated and compared to left ventricular angiography. Color kinesis is significantly superior to 2-D for all seven segments (mean 0.80/0.68, P = 0.05), except for the septum (0.67/0.60, P = NS). Interobserver variability studied by chi-square statistic is lower with color kinesis (0.70) than with 2-D (0.57). We conclude that these data suggest that color kinesis is a useful method for assessing systolic wall motion in all segments, except the septum and for improving the accuracy of segmental ventricular function and interobserver variability.

Adult↗

[Renocutaneous fistula: report of a chronic inguinal fistula].

The authors report a new case of isolated spontaneous nephrocutaneous fistula revealed by a persisting draining sinus in the left groin. Their present causative factors are identified. The computed tomography and magnetic resonance imaging actually may resolve the diagnostic dilemma and are helpful in the surgical treatment.

Adult↗

[Congenital tuberculosis: difficulties in early diagnosis].

BACKGROUND: Neonatal and/or congenital tuberculosis is insufficiently understood. CASE REPORTS: Case 1. A premature hypotrophic neonate presented at the age of 45 days, without any maternal contact, a bilateral bronchopneumopathy. Whilst the pregnancy and birth had not been affected by any noteworthy problem, the mother died from miliary tuberculosis despite rifampin, isoniazid and pyrazinamide treatment. Her baby also died on day 52 from multivisceral failure. Culture of tracheal secretions confirmed a few weeks later the diagnosis of tuberculosis. Case 2. A premature, hypotrophic neonate presented on day 22 signs of respiratory distress (miliary), icterus and hepatosplenomegaly. Whilst the pregnancy and birth had not been affected by any particular problem, the mother, 18 days after giving birth, presented miliary and pleural tuberculosis. Despite treatment with rifampin, isoniazid and pyrazinamid started on day 22, the baby died on day 27 from multivisceral failure. The post-mortem liver biopsy confirmed the diagnosis of tuberculosis. Case 3. A baby born at term was hospitalized on day 4 for jaundice. Whilst the pregnancy and birth had not presented any problem, the mother developed a pleural tuberculosis on day 10. Breast-feeding was stopped. Due to the presence of opacities at the top of the right lung, the child was given rifampin, isioniazid, and pyrazinamide. The course was marked by the appearance of hepatomegaly and poor weight gain up to day 25, followed by an improvement. CONCLUSION: The frequency of congenital tuberculosis is probably under-estimated. Its early diagnosis is essential but often difficult as the initial manifestations are delayed. Improved screening of women at risk and sensitization of the medical community are necessary.

Antitubercular Agents↗

[Pre-hospitalization treatment with Abciximab in the preparation of patients for primary angioplasty in the acute phase of myocardial infarct. Immediate and long-term (one month) results].

Percutaneous transluminal coronary angioplasty (PTCA) is an alternative to fibrinolysis in the treatment of acute myocardial infarction (AMI). However, after balloon PTCA, the rate of early re-occlusion, of re-infarctus and of restenosis remains high. Stent implantation with antiplatelet drug regimen (aspirin, ticlid) limits these risks. Abciximab (new GPIIb/IIIa receptors inhibitor) reduces PTCA complications rate in the acute coronary syndromes. Intravenous administration of abciximab can restore a normal flow in the infarcted related coronary artery (IRA) after few minutes. A monocentric, non randomized, prospective pilot study was iniated to assess the feasibility of pre-hospital treatment with abciximab in preparation to primary PTCA stenting in AMI (primary endpoint) and to appreciate potential benefits in initial IRA patency as well as prevention of PTCA thrombotic complications (secondary endpoint). Between April 1997 and January 1998, 38 AMI were treated with abciximab in pre-hospital phase (group A). Mobil Intensive Care Unit (MICU) team implemented the treatment and guaranteed immediate transport to the cathlab (abciximab bolus-coronary angiography time = 37 +/- 17 min). Immediate results were compared to those of 198 paired patients who were treated for AMI during the same period (Group T). Initial IRA flow TIMI grade 3 was significantly higher in group A, 24%, than in group T, 9% (p < 0.017). The rates of per-procedural complications (no flow, distal embolism), of local complications, of transfusions were not significantly different. During 1 month follow-up, there was no significant difference between group A and group T concerning death, re-MI, stent thrombosis and new revascularization. To conclude, the pre-hospital treatment with abciximab in AMI is feasible by MICU medical team without any delay of the cathlab admission. It is associated with no increased hemorrhagic complications rate. The abciximab pre-hospital treatment improves the initial IRA patency. These encouraging preliminary results expect to be confirmed by larger, multicentric, randomized and prospective studies.

Abciximab↗

Placement of coronary stents in bifurcation lesions by the "culotte" technique.

Coronary angioplasty of bifurcation lesions remains a technical challenge. Balloon angioplasty induces recoil and the "snow-plow" effect with a risk of side branch occlusion. The late result is associated with a high rate of reintervention. Randomized studies in nonbifurcated lesions have demonstrated better short- and midterm results after stent placement. We propose the "culotte" technique as a new technique to place intracoronary stents in bifurcation lesions: implantation of 2 similar stents in 2 steps in the main branch and in the side branch with overlapping of the 2 stents in the main branch before bifurcation. We performed this technique in 50 patients (in the left anterior diagonal branch in 33, in the left circumflex obtuse marginal branch in 12, in the right coronary artery in 4, and in the left main coronary artery in 1). The clinical success rate was 94% with 3 non-Q-wave myocardial infarctions. Late results indicated a 24% target lesion revascularization rate, which improved when a true kissing balloon inflation was used to achieve final deployment of both stents. This culotte technique is highly feasible and provides excellent short-term results. Assessment of its midterm benefit requires further study.

Angioplasty, Balloon, Coronary↗

[Myocardial infarction due to spontaneous coronary dissection during the postpartum period].

The authors report the case of a 34 year old woman, admitted to hospital because of myocardial infarction two months after delivery of her fifth child. The infarction was caused by spontaneous dissection of the left main coronary and left anterior descending arteries. Twenty-three months later, the patient was well with medical therapy. This case is an example of spontaneous post-partum coronary dissection which is the commonest cause of infarction occurring in that period. The physiopathology of this complication is not fully understood. The prognosis is poor, lethal in two thirds of cases. However, it must be emphasised that coronary dissection may regress spontaneously. Patients were previously referred systematically for surgery, but now it is usually reserved for cases with persistent myocardial ischaemia despite medical therapy. Angioplasty may be preferred despite the risks and may be successful in some cases.

Adult↗

[Left ventricular kinetics studied by the color kinesis method. Comparison of bidimensional echographic and angiographic data].

The object of this study was to assess the value of CK in the evaluation of left ventricular wall motion. Fifteen coronary patients aged 56 +/- 12 years were included: 8 patients were examined after acute myocardial infarction and 7 after unstable angina with a history of myocardial information. The left ventricle was divided into 7 segments after a modified Heger model, excluding the basal septal and basal lateral segments not seen on angiography. The left ventricular wall motion was assessed in two-dimensional echocardiography (2DE) and colour kinesis (CK) by two observers and compared with the results of left ventriculography, considered the reference method. Over all the 105 segments studied (7 segments for each of the 15 patients), CK was significantly better than 2DE (80% of segments correctly evaluated by CK vs 68% by 2DE, p < 0.05). Colour kinesis significantly improved the study of all segments except the interventricular septum (67% vs 60%, p = NS). The inter-observer variability in 2DE and CK evaluated over 135 segments (9 per patient) by the kappa was improved by colour kinesis (0.57 in 2DE, 0.7 in CK). The authors conclude that CK enables evaluation of left ventricular wall motion with greater precision and less inter-observer variability.

Aged↗

[Why so many stents?].

BETTER THAN ANGIOPLASTY: Prolonging inflation with a perfusion balloon decreases the risk of acute coronary occlusion after angioplasty. The longer the artery remains patent, the greater the chances of 0% residual stenosis. This is what the sent allows. Stent act on both mechanisms of stenosis: elastic recoil and fibrous remodeling of the arterial plaque. TARGETTED ACTION: Stents improve angioplasty prevention of acute stenosis. They have a real action on preventing degeneration of the saphenous graft and lead to a significant reduction in the rate of restenosis of the dilated site. There are however two specific complications: subacute occlusion and greater incidence of vascular events. Stents are particularly indicated for the treatment of restenosis and chronic occlusions. TWO IMPROVEMENTS: Risks related to the implantation of a foreign body in the vascular system have been reduced with the use of ticlopidine and high-pressure stent implantation. POSITIVE RESULTS: Stents have produced better angiographic results. They limit restenosis and the number of revascularizations required in treated patients. Several questions concerning indications remain open.

Angioplasty, Balloon, Coronary↗

[Medical treatment after implantation of intracoronary stents].

RATIONALE FOR ANTITHROMBOSIS THERAPY: Introducing a foreign body into the coronaries raises the risk of thrombosis in the acute phase and for the 4 following weeks. The objective of antithrombotic therapy is to inhibit platelet adhesion and aggregation or to induce hypocoagulability. AT IMPLANTATION: High-dose heparin is given in a bolus following pretreatment with aspirin. ASPIRIN-TICLOPIDINE COMBINATION: The risk of subacute thrombosis is low, about 1%, and the rate of vascular complications is minimal. Treatment is simple and compatible with short hospitalization.

Anticoagulants↗

[Different types of coronary stents].

GENERAL CHARACTERISTICS: Several criteria are used for coronary stent design: biocompatibility, i.e. the capacity to resist thrombotic events and corrosion, flexibility, radial force sufficient to resist elastic recoil, percentage of the lesion covered, radio-opacity, minimal shortening at opening, absence of effect on collateral branches, possibility to use small calibre probe guides, and cost. TWO CATEGORIES: Both tubular stents (self-expanding stents and balloon stents) and filamentary stents (made of stainless steel or tantalum) are used, THE IDEAL STENT: There is no one ideal stent. Choice is dictated by the characteristics of the lesion and by the status of the artery to treat.

Coronary Disease↗